Mixed organic amine absorbent as well as preparation method and application thereof

Abstract

The invention discloses a mixed organic amine absorbent as well as a preparation method and application thereof. The absorbent consists of a main absorbent, an absorption enhancer, a regulator and a solvent, the mass ratio of the main absorbent to the absorption enhancer to the conditioning agent is (0.5-5.0): (0.2-4.0): 1.0; the total mass concentration of the main absorbent, the absorption enhancer and the conditioning agent is 30-50 wt%; the main absorbent is diethylenetriamine, the absorption enhancer is N-methyldiethanolamine, the conditioning agent is 2-amino-2-methyl-1-propanol, and the solvent is water. According to the invention, by compounding and regulating the proportion of the organic amines, the synergistic effect of different types of organic amines is fully exerted, so that the mixed organic amine absorbent has high cycle capacity, low regeneration energy consumption, low absorbent loss, good dynamic performance and other good carbon dioxide capture performance.

Description

Technical Field

[0001] The invention relates to the technical field of absorbents, and in particular to a mixed organic amine absorbent and a preparation method and application thereof. Background Art

[0002] As the greenhouse effect continues to intensify, greenhouse gases, especially carbon dioxide (CO 2 ) emissions have received increasing attention. 2 Capture technology is a way to reduce CO 2 The chemical absorption method based on organic amines is the most mature and widely used capture method in carbon capture applications in coal-fired power plants due to its high absorption rate, large absorption capacity and low economic cost.

[0003] Although single-component organic amines have a 2 It has a certain affinity, but there are still some limitations. Specifically, polyamines with multiple primary / secondary amino groups have higher CO 2 absorption rate, but the absorption load is low, and the CO generated by the reaction 2 The product, carbamate, has a stable structure and high desorption heat. 2 The absorption load is high, and the absorption product bicarbonate is less stable and has a lower desorption heat requirement, but CO 2 The absorption rate is low and the mass transfer is limited. The above situation makes it difficult to screen out CO 2 The difficulty in finding absorbents with excellent capture performance and industrial application value, especially those with high circulation load and low total regeneration energy consumption, is a major bottleneck restricting the large-scale application of carbon capture.

[0004] Therefore, how to form a mixed amine absorption system by compounding multiple organic amines, give full play to the synergistic effect of organic amines with different structures, overcome the limitations of single-component organic amine absorbents in the carbon capture process, and form a mixed amine absorbent with strong absorption performance, high circulation capacity, low regeneration energy consumption, good kinetic performance and long-term operation has become an urgent problem to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a mixed organic amine absorbent and a preparation method and application thereof. The absorbent has strong absorption performance, high circulation capacity, low regeneration energy consumption, good kinetic performance and low organic amine loss.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a mixed organic amine absorbent, which mainly includes a main absorbent, an absorption promoter and a regulator; the mass ratio of the main absorbent, the absorption promoter and the regulator is (0.5-5.0):(0.2-4.0):1.0; the main absorbent is diethylenetriamine, the absorption promoter is N-methyldiethanolamine, and the regulator is 2-amino-2-methyl-1-propanol.

[0007] Optionally, the mass ratio of the main absorbent, the absorption enhancer and the regulator is preferably (1.0-4.0):(0.5-3.0):1.0.

[0008] Optionally, the mixed organic amine absorbent also includes solvent water, that is, the mixed organic amine absorbent consists of a main absorbent, an absorption promoter, a regulator and a solvent. In the mixed organic amine absorbent, the total mass concentration of the main absorbent, the absorption promoter and the regulator is 30 to 50 wt%.

[0009] Optionally, the absorption temperature of the mixed organic amine absorbent is 30-60°C.

[0010] Optionally, the regeneration temperature of the mixed organic amine absorbent is 100-140°C.

[0011] Optionally, the absorption load of the mixed organic amine absorbent is 0.45 to 0.65 mol CO 2 ·molAbsorbents -1 , the regeneration efficiency is 60.00%~86.00%.

[0012] Optionally, the circulation capacity of the mixed organic amine absorbent is 1.30 to 1.70 mol CO 2 kgSolutions -1 , the regeneration energy consumption is 1.8~2.6GJ·t CO 2 -1 .

[0013] Optionally, the amine escape amount of the mixed organic amine absorbent is 5 to 40 mg amine·Nm -3 The amine degradation rate is 0.10~0.45kg amine·t CO 2 -1 .

[0014] A second aspect of the present invention provides a method for preparing a mixed organic amine absorbent, the method comprising:

[0015] The main absorbent, absorption enhancer and regulator are mixed in a warm water bath and stirred for the first time to obtain a mixed solution; the mixed solution is placed in a cold water bath and solvent water is added for a second stirring to obtain a mixed organic amine absorbent; the mass ratio of the main absorbent, the absorption enhancer and the regulator is (0.5-5.0):(0.2-4.0):1.0; the main absorbent is diethylenetriamine, the absorption enhancer is N-methyldiethanolamine, and the regulator is 2-amino-2-methyl-1-propanol; the total mass concentration of the main absorbent, the absorption enhancer and the regulator is 30-50wt%.

[0016] Optionally, the first stirring speed is 400 to 900 r / min -1 , time is 20 to 60 min; the second stirring speed is 300 to 700 r·min -1 , time is 10 to 40 minutes; the temperature of the warm water bath is 30 to 50°C; the temperature of the cold water bath is 10 to 20°C.

[0017] The third aspect of the present invention provides the mixed organic amine absorbent provided by the first aspect of the present invention in CO 2 Capture applications.

[0018] Through the above technical scheme, the present invention uses diethylenetriamine as the main absorbent, N-methyldiethanolamine as the absorption promoter, and 2-amino-2-methyl-1-propanol as the regulator to form a mixed organic amine absorbent. By compounding and regulating the ratio between organic amines, the synergistic effect of different types of organic amines is fully exerted, the limitations of single-component organic amine absorbents in the carbon capture process are overcome, and CO 2 A mixed organic amine absorbent with strong absorption performance, high circulation capacity, low regeneration energy consumption, less absorbent loss and good kinetic performance.

[0019] Other features and advantages of the present invention will be described in detail in the following specific embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a comparison diagram of the absorption load of the mixed organic amine absorbent of the present invention and the 30 wt % monoethanolamine aqueous solution absorbent;

[0021] Figure 2 This is a comparison chart of the regeneration performance of the mixed organic amine absorbent of the present invention and the 30 wt % monoethanolamine aqueous solution absorbent;

[0022] Figure 3 The mixed organic amine absorbent of the present invention is used in CO 2 Capture the physical properties of each stage. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0024] The first aspect of the present invention provides a mixed organic amine absorbent, which includes a main absorbent, an absorption promoter, a regulator and a solvent; the mass ratio of the main absorbent, the absorption promoter and the regulator is (0.3-3.4):(0.5-2.7):1; the total mass concentration of the main absorbent, the absorption promoter and the regulator is 30-50wt%; the main absorbent is diethylenetriamine, the absorption promoter is N-methyldiethanolamine, the regulator is 2-amino-2-methyl-1-propanol, and the solvent is water.

[0025] The synergistic mechanism of the organic amines in the present invention is as follows: the main absorbent is a polyprimary / secondary amino organic amine, which contains two primary amino groups and one secondary amino group, each of which has high CO 2 Reactivity makes the main absorbent have higher CO 2 Absorption capacity and faster CO 2 reaction rate, but the primary / secondary amino functional groups absorb CO 2 The resulting carbamate is stable in nature and has poor regeneration efficiency. The absorption promoter has a tertiary amino functional group, which absorbs CO 2 The final product is bicarbonate, which has good regeneration performance. At the same time, the absorption promoter can replace part of the solvent water and reduce the regeneration latent heat. The primary / secondary amine main absorbent of polyamine group and the tertiary amine absorption promoter are mixed to reduce the high CO of primary / secondary amine. 2 Reactivity and high CO 2 The absorption load and excellent regeneration performance are combined to give full play to the synergistic effect of polyamines, making up for the shortcomings of single organic amine absorbents, thereby improving the CO 2 On this basis, the regulator is added to block the intermolecular hydrogen bonds by utilizing its low molecular planarity and strong steric hindrance, thereby preventing the polyamine primary / secondary amine from absorbing CO 2 The self-polymerization degree of the generated carbamate is too high, making it difficult for the absorption product to decompose, so as to improve the regeneration efficiency and reduce the regeneration energy consumption.

[0026] In addition, the boiling points of the three selected organic amines are significantly higher than the operating temperature range in the absorption-regeneration process, which can effectively reduce the amine loss caused by amine volatilization and reduce operating costs; at the same time, tertiary amines and high steric hindered amines have strong resistance to degradation and deactivation, which can effectively alleviate the degradation loss of the absorbent and increase the service life of the absorbent.

[0027] In summary, a mixed organic amine absorbent is finally constructed by compounding three types of organic amines, namely, polyamine primary / secondary amines, tertiary amines, and high sterically hindered amines. The mixed organic amine absorbent gives full play to the synergistic effect of different types of organic amines, and exhibits the performance advantages of fast absorption rate, high absorption load and circulation capacity, low regeneration energy consumption, good kinetic performance, and low organic amine loss.

[0028] According to the present invention, optionally, the mass ratio of the main absorbent, the absorption enhancer and the regulator is preferably (1.0-4.0):(0.5-3.0):1.0. Through the above preferred embodiment, the ratio of the main absorbent, the absorption enhancer and the regulator is within the above range, which can give full play to the synergistic effect of the three, so that the mixed organic amine absorbent has a fast absorption rate, high absorption load and circulation capacity, low regeneration energy consumption and good kinetic performance.

[0029] According to the present invention, optionally, the mixed organic amine absorbent further comprises solvent water, in which the total mass concentration of the main absorbent, the absorption promoter and the regulator is 30-50wt%. Through the above embodiment, the mixed organic amine absorbent has good absorption performance and regeneration performance.

[0030] According to the present invention, optionally, the absorption temperature of the mixed organic amine absorbent is 30-60°C. Within the above temperature range, the absorption load of the absorbent is 0.45-0.65 mol CO 2 ·mol Absorbents -1 .

[0031] According to the present invention, optionally, the regeneration temperature of the mixed organic amine absorbent is 100-140° C. Within the above temperature range, the regeneration efficiency of the absorbent is 60.00%-86.00%.

[0032] According to the present invention, optionally, the circulation capacity of the mixed organic amine absorbent is 1.30 to 1.70 mol CO 2 kg Solutions -1 , the regeneration energy consumption is 1.8~2.6GJ·t CO 2 -1 .

[0033] According to the present invention, optionally, the amine escape amount of the mixed organic amine absorbent is 5 to 40 mg amine·Nm -3 The amine degradation rate is 0.10~0.45kg amine·t CO 2 -1 .

[0034] A second aspect of the present invention provides a method for preparing a mixed organic amine absorbent, the method comprising:

[0035] The main absorbent, the absorption enhancer and the regulator are mixed in a warm water bath and stirred for the first time to obtain a mixed solution; the mixed solution is placed in a cold water bath and water is added to perform a second stirring;

[0036] The mass ratio of the main absorbent, the absorption promoter and the regulator is (0.5-5.0):(0.2-4.0):1.0; the main absorbent is diethylenetriamine, the absorption promoter is N-methyldiethanolamine, and the regulator is 2-amino-2-methyl-1-propanol.

[0037] According to the present invention, optionally, the first stirring speed is 400 to 900 r·min -1 , time is 20 to 60 min; the second stirring speed is 300 to 700 r·min -1 , time is 10 to 40 minutes; the temperature of the warm water bath is 30 to 50°C; the temperature of the cold water bath is 10 to 20°C.

[0038] The third aspect of the present invention provides the mixed organic amine absorbent provided by the first aspect of the present invention in CO 2 The mixed organic amine absorbent of the present invention absorbs CO 2 The conditions include: temperature of 30-60°C and pressure of 0.05-0.30Mpa.

[0039] The present invention is further illustrated by the following examples, but the present invention is not limited thereto.

[0040] Example 1

[0041] 11.71g of diethylenetriamine, 4.35g of N-methyldiethanolamine and 6.04g of 2-amino-2-methyl-1-propanol were mixed in a 40°C warm water bath and stirred for the first time to obtain a mixed solution; the mixed solution was placed in a 10°C cold water bath and 50g of water was added for a second stirring to obtain a mixed organic amine absorbent. The first stirring speed was 500r·min -1 , time is 30min; the second stirring speed is 400r·min -1 , time is 10 minutes.

[0042] Example 2

[0043] 13.37g of diethylenetriamine, 11.60g of N-methyldiethanolamine and 15.25g of 2-amino-2-methyl-1-propanol were mixed in a 35°C warm water bath and stirred for the first time to obtain a mixed solution; the mixed solution was placed in a 15°C cold water bath and 80g of water was added for a second stirring to obtain a mixed organic amine absorbent. The first stirring speed was 600r·min -1 , time is 25min; the second stirring speed is 500r·min -1 , time is 15 minutes.

[0044] Example 3

[0045] 30.02g of diethylenetriamine, 12.88g of N-methyldiethanolamine and 25.53g of 2-amino-2-methyl-1-propanol were mixed in a 30°C warm water bath and stirred for the first time to obtain a mixed solution; the mixed solution was placed in a 20°C cold water bath and 100g of water was added for a second stirring to obtain a mixed organic amine absorbent. The first stirring speed was 600r·min -1 , time is 20min; the second stirring speed is 500r·min -1 , time is 20 minutes.

[0046] Comparative Example 1

[0047] 12.36g of diethylenetriamine, 20.36g of N-methyldiethanolamine and 1.89g of 2-amino-2-methyl-1-propanol were mixed in a 50°C warm water bath and stirred for the first time to obtain a mixed solution; the mixed solution was placed in a 20°C cold water bath and 90g of water was added for a second stirring to obtain a mixed organic amine absorbent. The first stirring speed was 600r·min -1 , time is 15min; the second stirring speed is 500r·min -1 , time is 20 minutes.

[0048] Comparative Example 2

[0049] 35.86g of diethylenetriamine and 15.71g of N-methyldiethanolamine were mixed in a 45°C warm water bath and stirred for the first time to obtain a mixed solution; the mixed solution was placed in a 20°C cold water bath and 120g of water was added for a second stirring to obtain a mixed organic amine absorbent. The first stirring speed was 400r·min -1 , time is 50min; the second stirring speed is 600r·min -1 , time is 20 minutes.

[0050] Test Case

[0051] Absorbent absorption process: The mixed organic amine absorbents prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were placed in a simulated flue gas at 0.05 to 0.30 MPa, 30 to 60 °C, and CO 2 Absorbs CO at a concentration of 5.0 to 20.0 vol% 2 .

[0052] Absorbent regeneration process: After the absorption reaction, the mixed organic amine absorbent is placed under the conditions of stirring speed of 500-1500rpm and oil bath temperature of 100-140℃ to desorb CO 2 .

[0053] The circulation capacity, absorption load and regeneration efficiency of the mixed organic amine absorbents prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were measured and calculated. The results are shown in Table 1.

[0054] Circulation capacity: the unit mass of organic amine absorbent solution in the rich liquid (kg) to absorb CO 2 The amount of CO (mol) is related to the unit mass of organic amine absorbent solution (kg) in the lean liquid after desorption. 2 The difference in amount (mol).

[0055] Absorption load: CO absorbed by organic amine absorbent per unit amount of substance 2 The amount (mol CO 2 ·molAbsorbents -1 ).

[0056] Regeneration efficiency: The regenerated absorbent absorbs CO 2 The absorption load after CO absorption by fresh absorbent 2 The ratio of the absorbed load after.

[0057] Table 1

[0058]

[0059] It can be seen from Table 1 that the mixed organic amine absorbents prepared in Examples 1 to 3 of the present invention have higher circulation capacity, absorption load and regeneration efficiency than those in Comparative Examples 1 to 2, and thus the reaction absorbent has better absorption rate and regeneration rate, and lower regeneration energy consumption.

[0060] like Figures 1-2 As shown in the figure, under the conditions of the optimal mass ratio and the optimal total mass concentration of the main absorbent, the absorption promoter and the regulator, the absorption-regeneration performance of the mixed organic amine absorbent of the present invention reaches the best, which is significantly better than the commercial 30.0wt% monoethanolamine aqueous solution absorbent. 2 The characteristics of each stage of capture are as follows Figure 3 as shown

[0061] In addition, under the conditions of the optimal mass ratio and the optimal total mass concentration of the main absorbent, the absorption promoter and the regulator, the regeneration energy consumption of the mixed organic amine absorbent of the present invention is 1.8 - 2.4 GJ·t CO 2 -1 , which is significantly better than that of the 30.0 wt% monoethanolamine aqueous solution absorbent, 3.2 - 4.2 GJ·t CO 2 -1 ; the amine escape amount of the mixed organic amine absorbent of the present invention is 5 - 20 mg amine·Nm -3 , which is significantly better than that of the 30.0 wt% monoethanolamine aqueous solution absorbent, 40 - 100 mg amine·Nm -3 ; the amine degradation rate of the mixed organic amine absorbent of the present invention is 0.10 - 0.35 kg amine·t CO 2 -1 , which is significantly better than that of the 30.0 wt% monoethanolamine aqueous solution absorbent, 0.40 - 1.05 kg amine·t CO 2 -1 .

[0062] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0063] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any suitable way. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0064] Furthermore, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A mixed organic amine absorbent, characterized in that: Including main absorbent, absorption enhancer, and regulator; The mass ratio of the main absorbent, the absorption enhancer and the regulator is (0.5-5.0):(0.2-4.0):1.0; The main absorbent is diethylenetriamine, the absorption promoter is N-methyldiethanolamine, and the regulator is 2-amino-2-methyl-1-propanol.

2. The mixed organic amine absorbent according to claim 1, characterized in that: The preferred mass ratio of the main absorbent, absorption enhancer and regulator is (1.0-4.0):(0.5-3.0):1.

0.

3. The mixed organic amine absorbent according to claim 1, characterized in that: It also includes solvent water. In the mixed organic amine absorbent, the total mass concentration of the main absorbent, the absorption promoter and the regulator is 30-50wt%.

4. A method for preparing the mixed organic amine absorbent according to any one of claims 1 to 3, characterized in that: The following steps are involved: The main absorbent, the absorption accelerator and the regulator are mixed in a warm water bath and stirred for the first time to obtain a mixed solution; the mixed solution is placed in a cold water bath and water is added to perform a second stirring to obtain a mixed organic amine absorbent.

5. The method for mixing an organic amine absorbent according to claim 4, characterized in that: The first stirring speed is 400-900 r·min -1 , time is 20~60min; The second stirring speed is 300-700 r·min -1 , time is 10 to 40 minutes.

6. The method for mixing an organic amine absorbent according to claim 4, characterized in that: The temperature of the warm water bath is 30-50°C, and the temperature of the cold water bath is 10-20°C.

7. Use of the mixed organic amine absorbent according to any one of claims 1 to 3 in carbon capture.

8. The use according to claim 7, characterized in that: The absorption temperature of the mixed organic amine absorbent is 30-60°C.

9. The use according to claim 7, characterized in that: The regeneration temperature of the mixed organic amine absorbent is 100-140°C.

10. The use according to any one of claims 7 to 9, characterized in that: The absorption load of the mixed organic amine absorbent is 0.45 to 0.65 mol CO2·mol Absorbents -1 , regeneration efficiency is 60.00%~86.00%, and circulation capacity is 1.30~1.70mol CO2·kg Solutions -1 , the regeneration energy consumption is 1.8~2.6GJ·t CO2 -1 , amine escape is 5~40mg amine·Nm -3 , the amine degradation rate is 0.10~0.45kg amine·t CO2 -1 .

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